Re: [PSUBS-MAILIST] Trying again, Help a newbie

[Brandon Macmillan <2bitcomputers@gmail.com>]

Thanks for the fast response! You bring up many points that I had not
thought of before (always a good thing)

I had planed from the start to use Optima gel cell batteries
(http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/marine.html)
for exactly the reason that you pointed out, they are non-spilable. I
hadn't considered the hydrogen that they produce though, I was
thinking that they only do that when charging... I was just going to
seal them in a water tight hatch that would be opened when charging,
is that not the way to do it on a wet sub?

Full face scuba mask, that's what I meant. Though I still may go full
dry suit as the cold water is why I stoped diving before. I live in
Vancouver Canada, the water isn't THAT cold, but I'm a wimp :)

2-4 hour battery life, I want to be able to travel for a good distance
on the surface before diving at my dive site, I don't have a boat so I
would use this sub to transport me to the dive site and do my dive.
Typical dive times are going to be < 30 mins

Why does it need to fly/do rolls?

Well lets look at the purpose of this sub. Building a 1 Atm sub is
beyond my abilities and budget so reaching depths that I cant reach
with SCUBA isn't my goal. I can already ascend and descend with a BCD
when diving, so that's not the point. The point of this sub is pure
fun, I want it to be quick and responsive and to basically goof around
the whole time I am submerged. Think of it as an underwater go cart.

Wings? 

Because I saw the Deep Flight sub and though that it was a cool
idea... Also I fly model airplanes and know alot about that method of
control, and its generally how my brain works.

Boat motors....

Damn I thought they would work to 100'. time to do some re-thinking, I
was going to use trolling motors because I could use off the shelf
components saving time and money. If I have to take it apart and
re-build it I might as well start from scratch and build a thruster.
Like I said I know ALOT about electric motors and propellers and stuff
from my RC plane hobby. I think I could make a much more efficient
motor by using brushless motors, just alot more expensive and complex.
hmm....

This is pretty close to what I have in mind (
http://www.deepflight.com/subs/wf.htm ) but I wanted to make it a
2-man and a siting position not lying prone.  I also don't want to be
in a bubble because I would like to be able to take off my mask and
regulator when surfaced and ride around.

So many things to consider...

One more thing, I am thinking of making the main structure out of tube
frame and then mounting everything else to it to build it up. Steel or
Aluminium?





On 5/31/05, Akins <lakins1@tampabay.rr.com> wrote:
>  
> Hi Brandon. 
>   
> There are others at this forum more knowledgable than I that might help you
> with certain technical aspects that I cannot, but I will endeavor to help
> and advise you as best I can. 
>   
> First let me say that you must be dedicated to building this sub completely.
> Otherwise it will wind up an unfinished project. Even a susposedly simple
> wetsub can be quite complicated actually. I know. I own one. 
>   
> I will address your concerns and question in order. 
>   
> 1. You do not need a dry suit to have audio communications. You just need a
> full face mask with communications built into the mask. 
>   
>   
> 2. If you want to do barrel rolls you cannot use cheap, easily available car
> or marine deep cycle batteries. If you roll frequently you will spill your
> acid out into the interior of your battery compartment using those types of
> batteries so you will 
>   
> have to use more expensive non lead acid batteries in your design if you
> want to barrel roll the sub. Also you want stability in your wetsub so that
> means you need most of your buoyancy high and your weight low. Most people
> put their 
>   
> batteries and ballast low in order to keep stability and to keep from
> rolling over inadvertently. Rolling might sound like fun but why? In order
> to design your sub to roll it will cause you more design work and problems
> with the batteries and ballast 
>   
> weight. Most battery powered wetsubs are keel heavy for stability so they
> will not roll over. You can build a rolling wetsub, but it is more
> complicated. 
>   
>   
> 3. Trolling motors are made in other voltages besides 12 volts. My 74lbs
> thrust minnkota is 24 volts. 
>   
> Trolling motors companies like minnkota will only guarantee their products
> to 33ft. They are not made to go to deeper pressures. Now you get into
> either oil filling your trolling motors or air equalization, or have special
> ceramic prop shaft seals made to keep water 
>   
> pressure out of the motor. You will have to decide which system you want to
> use. Or you could strap a couple of sea scooters onto your sub that are
> already rated for at least 100 ft and believe me you might want to seriously
> think about that since you would not 
>   
> have to go thru the whole ceramic seal/air equalization/oil filled trolling
> motor thing. Also there is the hydrogen explosion problem from the batteries
> and isolating the motor from the battery gases going thru the wire strands
> and the tubing from the battery 
>   
> compartment to the motor. By the time you get thru messing around making a
> trolling motor work to 100 depth and adapting that motor and building a
> battery compartment and either oil or air equalize it, then making sure you
> vent the battery compartment 
>   
> properly to let hydrogen out when you charge....AHHHHHH! Trust me, think
> about scooters strapped to a wingtank. Then you could barrel roll all you
> wanted without a heavy battery pod under the sub. If you don't have that
> heavy battery pod keel then you might have 
>   
> a tendency to roll inadvertently. You could install ailerons on the dive
> planes to correct that roll when you are at speed, but you might not be able
> to control your rolling when you were stationary since you would not have a
> heavy keel for stability. 
>   
> Since you cannot dive to 100ft for 2 and 4 hours because of dive table
> preclusions, I assume you simply want that much battery time for multiple
> dives. Most times I will only dive two times on a given dive. Sometimes 3.
> You really do not need that much 
>   
> battery time and will only add unnecessary weight by needing more and larger
> batteries for that length of time. Two good quality (read that EXPENSIVE)
> powerful sea scooters with around 90 minutes of constant run time is all you
> really need. 
>   
> Two weeks ago I dove to 55ft spearing grouper on a reef. I used my sea
> scooter on two of my three dives that day. It has a run time of 90 minutes
> on full speed. If necessary I can surface and quickly and easily change out
> batteries and get another 90 minutes. 
>   
> You can't do a rapid battery change using a battery pod on your sub's keel.
> Trust me on this one and consider using dpv scooters as propulsion for your
> wetsub. 
>   
>   
> 4. Why do you want wings? They are not necessary. They do not hold you up
> like they do an aircraft. Dive planes will suffice. Possibly ailerons on
> your dive planes if you want to barrel roll. Let me ask you.....will you
> ever get out of the wetsub while underwater? 
>   
> What if you see something you want to retreive? You can't do that if you are
> slightly positive buoyant. The sub would float to the surface. Also I am not
> nuts about a slightly positive buoyant wetsub. When you do your 3 minute
> hang at 15 feet for no decompression 
>   
> diving, how are you going to do that once you stop the subs forward movement
> and the dive planes no longer hold you down? You will not like having a
> wetsub you can never park on the bottom. What you need are a couple of
> bladders or small ballast tanks that 
>   
> you can vary your buoyancy with. Put one in the bow and one in the stern.
> Have seperate lines going to them from your air tank so you can trim the
> boat. If you do not barrel roll, then you can drill a hole in the bottom of
> the ballast tanks to make sure you never 
>   
> overill and burst them. Also think about this....if you are in a bow up
> attitude, your air will go the the uppermost portion of your bow ballast
> tank right? Suspose you want to drop the bow to make the sub level called
> trimming the boat. You would want to make sure 
>   
> your air release valve or hose on the ballast tank was built into that end
> of the ballast tank, otherwise the air would be trapped above the valve or
> hose and not exit the tank. 
>   
> 5. Although once certified as a diver in the U.S. you are always certified.
> Your diving certificate does not expire here. However if you have not done
> it in a long time I would recommend a refresher course definately. It is
> suicidal and foolish for anyone to operate a wetsub 
>   
> without being a diver first. 
>   
>   
> 6. How much will it cost? That depends on your design. I would recommend a
> military surplus kevlar wingtank from a helicopter that is 15 ft long, about
> 1/2 inch thick and very strong. Cut out your cockpits, install your pivoting
> dive planes, rudder and sea scooters. 
>   
> You could avoid dive planes altogether and just use pivoting sea scooters in
> place of dive planes. Make the scooter removable so you can detach them and
> use them for normal diving without the sub. 
>   
> Then install your buoyancy bladders or ballast tanks. It will be as
> expensive or as cheap as you make it. But I guarantee if you make it
> correctly you will have more than a few thousand dollars in it. 
>   
> Figure what you THINK it will cost. Then multiply that number by 3. That
> will put you about right. 
>   
> Hope this helped. 
>   
> Kindest Regards, 
>   
> Bill Akins. 
>   
>   
>   
>   
>   
>   
>   
>   
>   
>   
>   
>   
>   
>   
>  
> ----- Original Message ----- 
> From: Brandon Macmillan 
> To: personal_submersibles@psubs.org 
> Sent: Tuesday, May 31, 2005 9:27 PM 
> Subject: [PSUBS-MAILIST] Trying again, Help a newbie 
> 
> Hey I just joined your mailing list. I saw a sub on a TV program and
> it sparked my interest, now I am looking into building one. I was
> wondering if you guys could help me get a better understanding of what
> I am getting into and the overall cost of such a project. The sub I
> saw on TV was always positively buoyant and 'flew' around underwater
> using a reverse hydrofoil to allow it to descend thus eliminating the
> need for a ballast tank/system. I think that's a pretty cool idea.
> What I have in mind is a WET sub, 2 man, powered by 2 12v trolling
> motors and deep cycle optima batteries. Air would be provided by 2 or
> 4 (haven't decided) scuba tanks and both the pilot and the passenger
> would use a scuba regulator (possibly a dry suit setup so we can
> communicate)
> 
> I plan to sit the pilot in the rear with the passenger below and in
> front of him in some sort of plastic bucket seat with a 5-point belt
> like a race car, control would involve pitching both motors up and
> down for ascent and decent and also for roll control (what good is a
> sub if you can't do barrel rolls) and either one large rudder or 2
> small ones attached to the backs of the motors. I would like a run
> time of aprox 2-4 hours and a depth of 100' Add on some powerful
> lights and a camera etc to the power budget. I would like to tow the
> sub on a trailer.
> 
> Also this thing has to look COOL. Since I am going to have wings of
> some kind I want to make it look like some sort of space fighter jet
> on steroids or like a POD racer from starwars. Sub is for recreation
> only.
> 
> I have done scuba diving in the past but would have to re-cert
> (something I plan to do anyways) and I can weld and fabricate pretty
> well (I have a 4x4 that some would consider at the extreme end of
> custom)
> 
> What kind of cost am I looking at for something like this, I think I
> am saving alot of money by having a WET sub and no ballast system.
> Safety factor is high because the sub will return to the surface in
> the event of failure as it always remains marginally positively
> buoyant, and I plan to have an emergency pony bottle between my legs
> in case I have to abandon ship.
> 
> 
> Where to start....
> 
> 
> 
> 
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-- 
Brandon Macmillan, Owner 2Bit Computers www.2bitcomputers.com




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